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Developing a New Understanding of the Evolution of the Newfoundland-Iberia Conjugate Margins and Its Impact on Petroleum Prospectivity


For the past 25 years, the main focus of North Atlantic exploration has been the syn-rift succession within the Jeanne d'Arc Basin, and more recently, the same plays have been pursued successfully in the northern Flemish Pass Basin. The Jeanne d'Arc Basin contains 18 oil and gas discoveries and has produced over 1.6 billion barrels of oil, with discovered reserves/resources of 3.9 billion barrels of oil and 12.6 trillion cubic feet of natural gas. At present, the Jeanne d'Arc Basin is the only significant oil province in the northwest Atlantic. Conjugate to Newfoundland is the West Iberian margin of Europe where the Lusitanian Basin has been the main focus of exploration. Results across this margin have been disappointing: of the ~175 wells drilled to date, only 16 of them have recorded oil and/or gas shows, of which, only 2 of these wells produced oil on testing, albeit at uncommercial levels. In order to develop a better understanding of petroleum prospectivity and potential exploration risk across the conjugate North Atlantic margins, we have undertaken an investigation of the evolution of the North Atlantic petroleum systems through time. We have done this by bringing together a detailed understanding of the region's plate tectonics, structural history, palaeogeography and Earth system models in order to then make comparisons between the conjugate margins. The ultimate aim of this study was to build a dynamic landscape model that brings together tectonics, surface processes and climate, with which explorationists can confidently predict depositional systems, including qualitative sediment volumes, composition and distribution. This model has the ability to expand interpretations beyond the extent of existing data (e.g. wells, outcrops). Such models implicitly include information on the underlying tectonics that can influence the nature and timing of trap formation, expulsion and burial history. Results show that there are similarities and differences between the petroleum systems of Newfoundland and the West Iberian margin. Both margins have Upper Jurassic–Lower Cretaceous, syn-rift, fluvio-deltaic, clastic reservoirs, with the main sediment supply provided by the uplift and erosion of Avalon Uplift (Newfoundland) and Iberian Meseta (West Iberian margin) basement terrains. The key differences between the petroleum systems are related to disparities in the timing and duration of main source rock deposition and thermal maturation along the two margins.